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International Refereed Journal of Engineering and Science (IRJES) is a peer reviewed online journal for professionals and researchers in the field of computer science. The main aim is to resolve emerging and outstanding problems revealed by recent social and technological change. IJRES provides the platform for the researchers to present and evaluate their work from both theoretical and technical aspects and to share their views.
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G224553

  1. 1. International Refereed Journal of Engineering and Science (IRJES)ISSN (Online) 2319-183X, (Print) 2319-1821Volume 2, Issue 2(February 2013), PP.45-53www.irjes.com Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in shear: A review M.B.S Alferjani1, A.A. Abdul Samad 1, Blkasem. S Elrawaff 2,N. Mohamad1, M.Hilton 1 and Abdalla Ab Sinusi Saiah3 1 Faculty of Civil and Environmental Engineering, UTHM University, Malaysia 2 Department Civil Engineering, Omar Mukhtar university, libay 3 Faculty of Techonogy Management, UTHM University, Malaysia ABSTRACT: The use of Fiber Reinforced Polymer (FRP) is becoming a widely accepted solution forrepairing and strengthening ageing in the field of civil engineering around the world. Several researches havebeen carried out on reinforced concrete beams strengthened with fiber reinforced polymer composite. Some ofthe works were focused on shear strengthening compared with flexural strengthening that had the largest share.This paper reviews 10 articles on carbon fiber reinforced polymer strengthened reinforced concrete beams.Finally, this paper attempts to address an important practical issue that is encountered in shear strengtheningof beams with carbon fibre reinforced polymer laminate. This paper also proposes a simple method of applyingfibre reinforced polymer for strengthening the beam with carbon fibre reinforced polymer.Keyword- carbon fibre reinforced polymer, concrete beams, flexural strengthening, shear strengthening I. INTRODUCTION The external bonding of high-strength Fiber Reinforced Plastics (FRP) to structural concrete membershas widely gained popularity in recent years, particularly in rehabilitation works and newly builds structure.Comprehensive experimental investigations conducted in the past have shown that this strengthening methodhas several advantages over the traditional ones, especially due to its corrosion resistance, high stiffness-to-weight ratio, improved durability and flexibility in its use over steel plates. The use of fiber reinforced polymer(FRP) materials in civil infrastructure for the repair and strengthening of reinforced concrete structures and alsofor new construction has become common practice. The most efficient technique for improving the shearstrength of deteriorated RC members is to externally bond fiber-reinforced polymer (FRP) plates or sheets [1].FRP composite materials have experienced a continuous increase of use in structural strengthening and repairapplications around the world, in the last decade [2].In addition, when the FRP was compared with steelmaterials, it was found that it provided unique opportunities to develop the shapes and forms to facilitate theiruse in construction. Although, the materials used in FRP for example, fiber and resins are relatively expensivewhen compared with traditional materials, noting that the crises of equipment for the installation of FRP systemsare lower in cost [3]. A review of research studies on shear strengthening, however, revealed that experimentalinvestigations are still needed [4, 5]. The use of carbon fiber-reinforced polymers (CFRP) can now beconsidered common practice in the field of strengthening and rehabilitation of reinforced concrete structures.The effectiveness of this technique is widely documented by theoretical and experimental researches and byapplications on real structures. As a consequence, the need of codes is necessary, leading to the development ofguidelines in different countries [6]. The CFRP strengthening provides additional flexural or shearreinforcement, the reliability for this material application depends on how well they are bonded and can transferstress from the concrete component to CFRP laminate [7]. Also, CFRP has made this technique even moreacceptance worldwide. Commercially available FRP reinforcing materials are made of continuous aramid(AFRP), carbon (CFRP), and glass (GFRP) fibers. Possible failure modes of FRP strengthened beams areclassified into two types; the first type of failure includes the common failure modes such as, concrete crushingand FRP rupture based on complete composite action, the second type of failure is a premature failure withoutreaching full composite action at failure. This type of failure includes: end cover separation, end interfacialdelamination, flexural crack induced debonding and shear crack induced debonding. Different failuremechanisms in experimental tests were reported by [8-10]. A more in depth explanation of these failure modescan be found in [11, 12]. Although CFRP composites are known to perform better under environmental actionthan glass fibre reinforced polymer laminates, no significant differences were detected, seemingly because www.irjes.com 45 | Page
  2. 2. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams infailure was not due to rupture of the fibres [13]. In addition, several studies were conducted to identify methodsof preventing premature failure with the aim of improving the load capacity and ductility of RC beams.Researchers studied the use of end anchorage techniques, such as U-straps, L-shape jackets, and steel clamps forpreventing premature failure of RC beams strengthened with CFRP [8, 14-23]. II. APPLICATIONS OF FRP There are three broad divisions into which applications of FRP in civil engineering can be classified:applications for new construction, repair and rehabilitation applications, and architectural applications. FRPshave widely been used by civil engineers in the design of new construction. Structures such as, bridges andcolumns built completely out of FRP composites, have demonstrated exceptional durability and effectiveresistance to the effects of environmental exposure. Retrofitting with adhesive bonded FRP, has beenestablished around the world as an effective method applicable to many types of concrete structural elementssuch as; columns, beams, slabs and walls. It was there that the first on-site repair by externally bonded FRP tookplace, in 1991. Since then, strengthening by externally bonded FRP composites has been studied worldwide.This sudden increase in the use of FRP composites was attained after the 1995 Hyogoken Nanbu Earthquake inJapan. By 1997, more than 1,500 concrete structures worldwide had been reinforced with externally bondedFRP composites. Figure 1 shows the application of CFRP on site. The other application, use of FRP bars insteadof steel reinforcing bars or pre-stressing strands in concrete structures. Figure-1. Shear strengthening of Reinforced concrete using CFRP laminate. III. PREVIOUS RESEARCH WORKS ON BEAMS Investigation on the behaviour of CFRP retrofitted reinforced concrete structures has in the last decadebecome a very important research field. In terms of experimental application several studies were performed tostudy the behaviour of retrofitted beams and analyzed the various parameters influencing their behaviour. Khalifa et al (1999), carried out the test of three simply supports RC T-beams to study the effectiveness of anchorage of surface mounted FRP reinforcement. The first beam was a reference beam, the second beam strengthened with CFRP without end of anchor and the last beam strengthened with CFRP with end of anchor. The anchor system, called U-anchor used GFRP bar inserted in the groove in the beam flange used as end anchor. They found that the shear capacity increased when strengthened with CFRP but, failure was governedby debonding of CFRP when CFRP was used without end anchor. However, the specimen where the anchor was used, shear capacity of the member rather increased and, ultimately no FRP debonding was observed. Adhikary et al (2004), carried out the tests of eight simply supported RC beams strengthened for shearwith CFRP sheet using two different wrapping schemas; U-wrap and two sides of the beam. He investigated theeffectiveness of cross plies one over another, vertical and horizontal; the main parameter, direction of fiberalignment (90°,0°and 90°+0°) and number of layers (1 and 2). They observed that the maximum shear strengthwas obtained for the beam with full U-wrapped sheets having vertically aligned fibers. Horizontally alignedfibers also showed enhanced shear strengths as compared to beam with no CFRP. On the other part, they foundthat the lowest concrete strain was the same load range among all beams. The beam with full U-wrapping of asingle layer of CFRP with vertically aligned fibers, was observed at a maximum of 119% increase in shearstrength. Also, they compared with the experimental value, using models for the prediction of shear contributionof sheet to shear capacity of CFRP bonded beams. Al-Amery (2006), tested six RC beams; having various combinations of CFRP sheet and straps inaddition to an un-strengthened beam, as control test. CFRP provided (CFRP sheet for flexural strengthening andCFRP straps for shear strengthening or with a couple of CFRP sheets and straps, for overall strengthening. Fromthe experiment, two beams were tested in four-point bending over a total span of 2300 mm and a shear span of700 mm, while the rest RR3-RR6 were tested in three points bending over a total span of 2400mm and shear www.irjes.com 46 | Page
  3. 3. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams inspan of 1200 mm. The CFRP sheets consisted of three layers, while CFRP straps consisted of one layer andextra anchorage mechanism for the CFRP sheets. They observed that the used of CFRP straps significantlyreduced the interface slip between the CFRP sheets and the concrete section. CFRP straps used to anchor theCFRP sheets, increased in flexural strength of up to 95%. However, with the use of CFRP sheets alone, only anincrease of 15% was achieved. Test results and observations showed that was a significant improvement in thebeam strength was gained due to the coupling of CFRP straps and sheets. Furthermore, a more ductile behaviourwas obtained as the debonding failure was prevented. Anil (2006), improved the shear capacity of RC T-beams using unidirectional CFRP composites andcompared between the experimental and analytical used ACI Committee report. He tested six beams of sizes;120mm width 360mm depth 1750mm length and 75mm flange thickness. Of these, two beams were controlspecimen and four beams were strengthened with different configurations of CFRP strips, all these beams weretested under cyclic loading. These beams had longitudinal reinforcement and no stirrups for beams except one ofthe control beam. The parameters of this case were; 1) CFRP orientation of CFRP and , 2) spacing of CFRPwas 285 and 143mm, 3) CFRP strengthened scheme was both sides and U-wrap, 4) different compressingstrengths were used and 5) anchorage was used as steel plates on both sides and ( L-shaped). From the results,he observed that the stiffness of the beams were very close. He also observed that the strength and stiffness ofthe specimens improved by using CFRP unidirectional. On the other side, the analytical shear load capacityshowed 20% less than the experimental shear load capacity, due to using the successful performance ofanchorage. Bencardino et al (2007), presented an experimental and analytical investigation on the shearstrengthening of reinforced concrete rectangular beams wrapped with carbon fiber reinforced polymers (CFRP)laminates. A total of four beams were specifically designed, with and without an external anchorage system. Thecross sections of 140mm x 300mm with total length of 5000mm were used. The specimens were two controlbeams with different av/d, one beam with only CFRP and one beam with CFRP + external links. All beams hadidentical internal reinforcement and were tested under four point bending over an effective span of 4800 mmand no in the shear span but had stirrups in the near of support. The principle variables included externalanchorages, with different lengths in the mode of U-shaped steel stirrup. The results showed the anchoragesystem enhances the strength and deformability properties of the CFRP plated beam. Also, the anchorage systemmodifies the failure mode of the strengthened RC beam under predominant shear force, without increasing theload capacity, to a more ductile failure with a substantial increase of load carrying capacity to almost a flexuralfailure. Jayaprakash et al (2008), did an experimental investigation on shear strengthening capacity and modesof failure of pre-cracked and non-pre-cracked RC beams bonded externally with bi-directional Carbon FibreReinforced Polymer (CFRP) fabric strips. Twelve RC T- beams were fabricated with different internallongitudinal and shear reinforcements. These beams were subjected to two types of loading; namely three-pointand four-point bending systems. The beams were classified into three categories namely; control, precracked-repaired and initially strengthened (i.e. non-precracked) beams. The overall increase in shear enhancement ofthe precracked-repaired and initially strengthened beams ranged between 13% and 61% greater over theircontrol beams. It was found that the application of CFRP strips in the pre-cracked-repaired beams attained betterperformance as compared to the initially strengthened beams. It was also observed that all strengthened beamsfailed in premature flexural failure due to the presence of excessive amount of shear reinforcement. Jayaprakash et al (2008), conducted tests to study shear capacity of pre-cracked and non- pre-crackedreinforced concrete shear beams with externally bonded bi-directional CFRP strips. The experimental programconsisted of six specimens that were classified into two categories; namely BT and BS, each category had eightbeams, four control beams, six pre-cracked/repaired beams and six initially strengthened specimens. Therectangular beam had a dimension of 2980mm length, 120mm wide and 310mm depth. The variablesinvestigated within this program included longitudinal tensile reinforcement ratio ( = 1.69) for 20mm and ( =1.08) for 16mm, no steel stirrups, shear span to effective depth ratio (av/d=2.5 and av/d =4), spacing of CFRPstrips (80 mm @ 150 mm c/c and 80 mm @ 200 mm c/c) and orientation of CFRP strips (0/90 deg and 45/135deg) in 3 sides U- wrap schemes. From the results, they observed that the external CFRP strips act as shearreinforcement similar to the steel stirrups. They also showed that by increasing the amount of longitudinaltensile reinforcement ratio and spacing of CFRP strips, affect the shear capacity. This study found that theorientation of CFRP strips not only affects the cracking pattern but also affects the shear capacity. Godat et al (2010), studied to obtain a clear understanding of size effects for Carbon Fiber-ReinforcedPolymer (CFRP) shear-strengthened beams. Their experimental research presented here, investigated the shearperformance of rectangular reinforced concrete beams strengthened with CFRP U-strips as well as onecompletely wrapped with CFRP sheet. Seven rectangular RC beams were grouped into three test series, threecontrol beams, three beams with U-Shaped CFRP jacket and beam with completely wrapped external CFRPsheets. The cross sections were; first series 100mmx200mm with length 900mm, second series 200x400mm of www.irjes.com 47 | Page
  4. 4. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in length 1800mm and third series 300mmx600mm with beam length 2700mm. All beams were heavily reinforced in bending, no steel stirrups were installed in the right shear span of interest but in the left shear span,it was placed to ensure that the failure would occur in the shear span of interest. From these results, they observed that the larger beam size, CFRP sheet provided less improvement in the shear capacity. They investigated the cracking behaviour of these specimens. Their research presented a Comparison between Test Results and Predictions from Design Guidelines. Bukhaari et al (2010), studied the shear strengthening of reinforced concrete beams with Carbone Fiber Reinforced Polymer (CFRP) sheet. Seven, two span continuous reinforced concrete (RC) rectangular beams. The cross section of rectangular was 152mmx305mm and beam length 3400mm. One beam was un- strengthened (control beam)and, the remaining six were strengthened with different arrangements of CFRP sheet. They studied orientation of fiber (0/90 and 45/135) as main variables. The tests showed that it is beneficial to orientate the fibres in the CFRP sheet at 45 so that they are approximately perpendicular to the shear cracks. H.K. Lee, S.H. Cheong, S.K. Ha and C.G. Lee (2011), investigated the behaviour and performance of reinforced concrete (RC) T-section deep beams strengthened in shear with CFRP sheets. A total of fourteen reinforced concrete T-section deep beams were designed to be deficient in shear. The cross section of 180mmx460mm with flange thickness of 100 mm and the beam’s length of 1800mm, were used. The specimens were reinforced with longitudinal steel and stirrups near the mid-span. They also studied variables such as strengthening length, fiber direction combination of CFRP sheets, and an anchorage using U-wrapped CFRP sheets, these variables have significant influence on the shear performance of strengthened deep beams. Their tested Experimental results T-section beams were regarded as deep beams, since the shear span-to-effective depth ratio (a/d) was 1.22. On the other hand, Crack patterns and behaviour of the tested deep beams were observed during four-point loading tests. Table-1. Experimental results and numerical simulation of load-carrying capacity of reference RC beams Author / size of Beam No of Ancho Ultima Material Fcu Adh beam ID layer rage te load Failure mode MPa esive (mm) (mm) (kN) 24/150 BT1 - - 35 - Epoxy 180 Diagonal shear crackx405x305 BT2 CFRP sheet 1 35 No paste. 310 Shear compression0mm, BT3 CFRP sheet 1 35 yes 442 Flexural failureflangethickness=100mm 25/150 B-1 - - 30.5 - Primer 39.2 Diagonal shear x200 B-2 CFRP sheet 1 34.4 No and 50.5 Diagonal shear+ CFS rupture x2600 epoxy (horizontal). mm B-3 CFRP sheet 2 33.5 No 63.6 Shear crashing + CFS rupture (horizontal). B-4 CFRP sheet 1 31.5 No 58.6 B-5 CFRP sheet 2 31.0 No 60.3 Shear crashing + CFS debonding B-6 CFRP sheet 2 33.7 No 80.8 Shear crashing + CFS debonding Shear crashing + horizontal cracks B-7 CFRP sheet 1 34.4 No 68.5 at top face Shear crashing + CFS debonding + B-8 CFRP sheet 1 35.4 No 85.8 tearing Shear crashing + horizontal cracks at top face www.irjes.com 48 | Page
  5. 5. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in 26/140 RR1 - - 37.8 No Under 106.2 Shearx260x270 RR2 CFRP straps 1 39.5 Yes coat 121.4 Flexure0mm RR3 CFRP sheet 3 39.1 No and 100.3 Shear RR4 CFRP 3+1 39.4 No Over- 112.1 Flexure (CFRP break) straps+ sheet coat CFRP Resin RR5 3+1 39.0 Yes 126.3 Flexure (CFRP break) RR6 straps+ sheet 3+1 41.0 Yes 123.2 Flexure (CFRP break) CFRP straps +sheet 27/120 Beam-1 - - 33.0 - Epoxy 104.8 Flexurex360x175 Beam-2 - - 30.0 - resin 41.4 Shear0mm,flan Beam-3 CFRP strips 1 35.6 Yes 74.3 Shearge Beam-4 CFRP strips 1 35.8 Yes 89.9 Flexure-shearthickness Beam-5 CFRP strips 1 35.2 Yes 90.0 Flexure=75mm Beam-6 CFRP strips 1 35.0 Yes 91.9 Flexure 28/140 B2 - - 37.3 - Epoxy 57.5 Concrete crushingmm x 300 B2.1 - - 35.1 - resin 82.5 Shear crackmm5000 B2.2 CFRP 1 38.2 No 82.1 Shear crack mm laminates B2.3 CFRP 1 42.7 Yes 206.3 Slice end concrete section laminates 29/340 TT1a - - 27.4 - Epo 174.65 Shearx200x298 TT1-1 CFRP strips 1 27.4 No xy 241.16 Flexural 0mm TT1-1I CFRP strips 1 27.4 No resin 281.08 Flexural thickness TS1a - - 16.7 - (sikad 134.74 Shearflange=10 TS1-1 CFRP strips 1 16.7 No ur 330) 187.98 Flexural 0mm CFRP strips TS1-1I 1 16.7 No 121.44 Flexural TT2a - - 27.4 - 148.04 Shear TT2-2 CFRP strips 1 27.4 No 201.26 Flexural TT2-2I CFRP strips 1 27.4 No 214.56 Flexural TS2a - - 16.7 - 108.14 Flexural TS2-1 CFRP strips 1 16.7 No 148.04 Flexural TS2-1I CFRP strips 1 16.7 No 121.44 Flexural www.irjes.com 49 | Page
  6. 6. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in30/120x3 BT1aa - - 27.38 No Epoxy 98.14 Shear10x2980 BT1-I CFRP strips 1 27.38 No resin 134.73 Shear-CRP fracturemm BT1-1I CFRP strips 1 27.38 No (sikad 174.64 Shear-CFRP fracture BT1-2I CFRP strips 1 27.38 No ur 330) 134.73 Shear-CFRP fracture BS1a - - 27.38 No 74.86 Shear BS1-1 CFRP strips 1 27.38 No 121.42 Shear-CFRP fracture BS1-2 CFRP strips 1 27.38 No 101.46 Shear-CFRP fracture BT2a - - 16.73 No 64.88 Shear BT2-1 CFRP strips 1 16.73 No 134.73 Shear-CFRP fracture BT2-2 CFRP strips 1 16.73 No 121.42 Shear-CFRP fracture BT2-2I CFRP strips 1 16.73 No 154.68 Shear-CFRP fracture BS2a - - 16.73 No 61.56 Flexural BS2-1 CFRP strips 1 16.73 No 108.19 Flexural BS2-2 CFRP strips 1 16.73 No 81.51 Flexural BS2-2I CFRP strips 1 16.73 No 88.16 Flexural BS2-1I CFRP strips 1 16.73 No 68.21 Flexural31/a)100x RC1 - - 51.2 No Epoxy 160 Concrete crushing 200x900 U4 CFRP jacket 1 51.2 No resin 203 Debonding mm RC2 - - 49.7 No 709 Concrete crushingb)200x40 U5 CFRP jacket 1 51.2 No 809 Debonding0x1800m RC3 - - 50.5 No 1626 Concrete crushing m U6 CFRP jacket 1 51.0 No 2018 Debonding c)300x600x W7 CFRP sheet 1 50.7 No 2221 CFRP rupture 2700mm 32/152 C1 - - 60 - Epoxy 250 Shearx305x340 C2 CFRP sheet 1 60 No 384.7 Sheet delamination 0mm C3 CFRP sheet 1 60 No 423.2 Sheet delamination C4 CFRP sheet 1 60 No 383.2 Sheet delamination C5 CFRP sheet 1 60 No 452.0 Sheet rupture C6 CFRP sheet 1 60 No 480.9 Sheet delamination D6 CFRP sheet 1 44 No 461.7 Sheet delamination www.irjes.com 50 | Page
  7. 7. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in33/180x4 CT - - 22.45 - primer 458.2 shear-compression 60x1800 CS-QL-HP CFRP sheet 1 22.45 No and 528.6 shear-compression due to partial mm, saturan delamination flange CS-QL-VP CFRP sheet 1 22.45 No t resin 505.9 shear-compression due to partialthickness delamination= 100mm. CS-QL-CP CFRP sheet 1 22.45 No 512.9 . shear-compression due to partial CS-QL-AP CFRP sheet 1 22.45 No 525.3 delamination shear-compression due to partial CS-HL-HP CFRP sheet 1 22.45 No 599.4 delamination CS-HL-VP CFRP sheet 1 22.45 No 528.6 shear-compression due to partial delamination CS-HL-CP CFRP sheet 1 22.45 No 562.7 shear-compression due to partial delamination shear-compression due to partial CS-HL-AP CFRP sheet 1 22.45 No 547.2 delamination CS-FL-HP CFRP sheet 1 22.45 No 760.5 shear-compression due to partial delamination CS-FL-VP CFRP sheet 1 22.45 No 542.1 shear-compression due to rupture of CFRP sheets CS-FL-CP CFRP sheet 1 22.45 No 660.5 shear-compression due to partial CS-FL-AP CFRP sheet 1 22.45 No 646.5 delamination shear-compression due to partial delamination CS-FL-CP CFRP sheet 1 22.45 Yes 699.5 shear-compression due to partial delamination shear-compression due to partial delamination IV. COMMENTS ON THE ACTUAL STATE OF ART: V. From the above review of literature (Table-1), illustrates that although substantial research has been conducted on CFRP strengthening of reinforced concrete beams still, the behaviour of CFRP strengthened beams in shear was young as compared with strengthened beams in flexural. There is no design guideline for optimizing and choosing the thickness of CFRP sheet/laminate for strengthening RC beams. From the researchers conducted on RC rectangular and T-Beams sections which, were strengthened in shear with CFRP and which were strengthened with 1, 2 and 3 layers of CFRP laminate . VI. PROPOSED METHOD OF STRENGTHENING To overcome the problems stated above, the future new technique for strengthening the beam with CFRP uses different Options (Bonded Surface Configurations, End Anchor, Spacing and Fiber Orientation), to understand the behaviour of strengthened beam with CFRP laminates. The study parameters including end of anchorage, failure mode, orientation, number of layer, spacing, strength scheme and shear capacity must be investigated in shear strengthening with CFRP laminate. Finally, the proposed study is to improve the understanding of reinforced concrete beams retrofitted with CFRP and this proposal brings new challenges for professionals and who are working in the field of structural repair and strengthening of reinforced concrete structures and due to the latest technologies in binding the delamination concept can be totally eradicated. www.irjes.com 51 | Page
  8. 8. Use of Carbon Fiber Reinforced Polymer Laminate for strengthening reinforced concrete beams in VII. CONCLUSIONS This paper reviewed the existing research works on reinforced concrete beams strengthened by CFRP.The beam strengthened with more than one layer of CFRP laminate unnecessarily increased the strengtheningtime as well as cost by providing more than one layer of CFRP laminate. The importance of the study in thestrengthening of the beam using CFRP laminate in the strengthening system provides an economical andversatile solution for extending the service life of reinforced concrete structures. From the literature, it is evidentthat epoxy resin is favoured in strengthening and also the end of anchorage was used to eliminate the debondingfailure. Future research is needed for a complete awareness for strengthening reinforced concrete beams withFRP, with the aim to efficiently contribute in the concrete structures repair tasks as well as, to decrease thedimensional stability of the structure. A working knowledge of how material properties change as a function ofclimate, time and loading will also be of great value to the engineering and design communities. Moreover, FRPin concrete allows engineers to increase or decrease margins of safety depending on environmental and stressconditions, generic FRP type and required design life. VIII. ACKNOWLEDGMENTThe authors gratefully acknowledge the financial support from Fundamental Research Grant Scheme (FRGS)funded by Ministry of Higher Education, Malaysia. REFERENCES[1] Gyuseon Kim, Jongsung Sim and Hongseob Oh (2008). Shear strength of strengthened RC beams with FRPs in shear. Construction and Building Materials pp. 1261–1270.[2] Oral Buyukozturk, Oguz Gunes and Erdem Karaca (2004). Progress on understanding deboning problems in reinforced concrete and steel members strengthened using FRP composites. Construction and Building Materials pp. 9–19.[3] Shit, T.2011. Experimental and Numerical Study on Behavior of Externally Bonded RC T-Beams Using GFRP Composites. Department of Civil Engineering National Institute of Technology Rourkela,Orissa: : Masters Thesis.[4] Bousselham, A., and Chaallal, O., (2004),“ Shear Strengthening Reinforced Concrete Beams with Fiber-Reinforced Polymer: Assessment of Influencing Parameters and Required Research, ACI Structural Journal, V. 101, No. 2, Mar.-Apr., pp. 219-227[5] Matthys, S., and Triantafillou, T., (2001), “Shear and Torsion Strengthening with Externally Bonded FRP Reinforcement,” Proceedings of the International Workshop on Composites in Construction: A Reality, E. Cosensa, G. Manfredi, and A. Nanni, eds., Capri, Italy, pp. 203- 210.[6] Tan, K.Y. 2003. Evaluation of Externally Bonded CFRP System for the Strengthening of RC Slabs. University of Missouri-Rolla. Center for Infrastructure Engineering Studies: Masters Thesis.[7] Ekenel,M ., Stephen,V., Myers, J.J. & Zoughi,R.(2004). Microwave NDE of RC Beams Strengthened with CFRP Laminates Containing Surface Defects and Tested Under Cyclic Loading. Electrical and Computer Engineering, University of Missouri-Rolla, Rolla, MO 65409, USA, pp 1-8.[8] Aram MR, Czaderski C, Motavalli M (2008). Debonding failure modes of flexural FRP-strengthened RC beams. Composites Part B: Engineering. 39: 826-41[9] Pham H, Al-Mahaidi R (2004). Assessment of available prediction models for the strength of FRP retrofitted RC beams. Composite Structures. 66: 601-10[10] Teng GJ, Smith TS, Yao J, Chen JF (2003). Intermediate crack-induced debonding in RC beams and slabs. Construction and Building Materials. 17: 447-62[11] Smith S.T and Teng J.G. 2002. FRP-strengthened RC beams I: Review of Debonding Strength. Eng Struct. 24: 385-95.[12] Smith S.T and Teng J.G. 2002. FRP-strengthened RC beams. II: Assessment of Debonding Strength Models. Engineering Structures. 24: 397-417.[13] Manuel A.G. Silva and Hugo Biscaia. 2008. Degradation of Bond between FRP and RC Beams. Composite Structures. 85: 164-174[14] Ceroni F (2010). Experimental performances of RC beams strengthened with FRP materials. Construction and Building Materials. 24: 1547-59.[15] Jumaat MZ, Alam MA (2010). Experimental and numerical analysis of end anchored steel plate and CFRP laminate flexurally strengthened r. c. beams. Int. J. Phys. Sci. 5:132-144.[16] Wang YC, Hsu K (2009). Design recommendations for the strengthening of reinforced concrete beams with externally bonded composite plates. Composite Structures. 88: 323-32.[17] Alam MA, Jumaat MZ (2008). Behavior of U and L shaped end anchored steel plate strengthened reinforced concrete beams. 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Composite Structures. 92: 322-9.[23] Mohamed,B.B, Abdelouahed T, Samir B (2009). Approximate analysis of adhesive stresses in the adhesive layer of plated RC beams. Computational Materials Science. 46: 15-20.[24] Khalifa, A., Alkhrdaji, T., Nanni, A. & Lansburg, S. (1999). Anchorage of Surface Mounted FRP Reinforcemen.Concrete International: Design and Construction, Vol. 21, No.10, pp. 49-5.[25] Adhikary, B.B.,ASCE,M. &Musuyoshi, H. (2004). Behavior of Concrete Beams Strengthened in Shear with Carbon-Fiber Sheets. Journal of Composites for Construction Vol. 8, No.3, pp. 258-264. www.irjes.com 52 | Page
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